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Wednesday, 28 January 2009

There are some people, who, when they telephone, say "Hello, it's me!" Although rather endearing, such people, by doing this, aren't being sensitive to the needs of people with phonagnosia - the inability to recognise a person's identity from the sound of their voice.

Previously, phonagnosia had only been documented in people who had developed the condition after sustaining a brain injury. Now Lúcia Garrido and colleagues have provided what they believe is the first ever description of a case of developmental phonagnosia - that is, the presence of the condition in a woman with no apparent brain damage.

KH, a female, aged 60 at the time of her testing, told the researchers that she had always had difficulty recognising who people were from the sound of their voices. Garrido's team confirmed this in a series of comprehensive lab tests. KH was unable to tell famous voices, such as David Beckham's, from non-famous ones and was unable to learn to associate new voices with the names of their owners. By contrast, she was able to identity environmental sounds, recognise familiar music and infer emotions from both non-verbal sounds and speech.

It seems phonagnosia can join a growing list of specific impairments that can either be acquired through brain injury or present from birth or early childhood. Others include prosopagnosia (the inability to recognise faces; until recently it was thought this condition only arose through injury), dyscalculia (a deficit with numbers), dyslexia, amusia (a musical deficit) and specific language impairment.

The researchers said the existence of phonoagnosia provides support for a modular account of voice processing - this is the idea that different aspects of voices, such as emotion and identity, are processed independently in the brain.

"Other selective developmental conditions have shed light on the cognitive, neural, developmental and genetic basis of particular abilities," they concluded, "and we expect that developmental phonagnosia will provide a means to address these issues for voice processing."
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